The invention relates to a method for pre-climatizing a stopped motor vehicle by way of a heating and/or cooling unit, which draws its energy for heating and/or cooling from an electric storage unit, as well as to a corresponding motor vehicle with a heating and/or cooling unit for carrying out the method.
In order to be able to optimally control the temperature of a stopped motor vehicle, there exist currently a variety of devices and methods. DE 197 31 071 A1 discloses a system, which is intended for controlling the temperature of the interior of a stopped motor vehicle. In this case, the method utilizes the residual heat that is still present in the vehicle and which comes from a heat source, as well as the residual coldness that is still present in the vehicle and which comes from a refrigeration source.
Since the utilization of residual heat and/or residual coldness is possible only if the heat sources and/or the refrigeration sources that are used to this end are in a state, in which they can dissipate heat and/or coldness—therefore, as a rule, immediately following a (prolonged) operation of the motor vehicle—such systems are often not sufficient to facilitate an optimal temperature control of the interior of a stopped motor vehicle.
In addition to the afore-mentioned devices for controlling the temperature of the interior of a stopped vehicle, supplementary heating units, auxiliary heating units and/or electrically driven cooling units, which usually obtain their energy with the aid of internal combustion engines or thermal energy storage units, are often used for heating or cooling the vehicle when in a stopped mode. Such heating and/or cooling units have an enormous fuel consumption and are, therefore, associated with the emission of an undesirably high quantity of pollutants.
New vehicle concepts, in particular hybrid vehicles, suggest an approach that utilizes the necessary energy for operating the heating and/or cooling units in the stopped state from the existing electric energy accumulators. Thus, DE 10 2005 004 950 A1 discloses an air conditioning system for a hybrid vehicle. In this case, air preconditioning is made possible by an electric refrigerant compressor, which is already mass produced and present in the system and which is activated by a traction battery of the vehicle. Even though such systems have the advantage that air preconditioning is possible without the emissions from an internal combustion engine or a fuel fired heating unit, the air preconditioning is possible only for a limited period of time owing to the storage capacity of the electric accumulators. As soon as the charge state is, or falls, below a predetermined limit value, an air preconditioning is not possible (any longer), since otherwise the operation of the motor vehicle could be put at risk. The result would be an enormous loss in comfort and convenience for the driver.
The object of the invention is to provide a method and a device for pre-climatizing a stopped motor vehicle without the emission of pollutants. In this context, air preconditioning can be guaranteed for the longest possible time and/or the useful period for the customer.
This object is achieved by a method, and correspondingly equipped motor vehicle, for pre-climatizing a stopped (shut-off) motor vehicle by way of a heating and/or cooling unit, which draws its energy for heating and/or cooling from an electric storage unit. When the heating and/or cooling unit is activated by a vehicle external operator control element, the heating and/or cooling unit can be operated in at least two output stages. When the heating and/or cooling unit is activated in the stationary state, the heating and/or cooling unit is activated in a first output stage, and the heating and/or cooling unit is switched from the first output stage into a second output stage as a function of the predetermined conditions. Advantageous further developments are described herein.
According to an aspect of the invention, energy for pre-climatizing the interior of the vehicle is taken from the electric storage unit. Furthermore, it is assumed that in the event that the driver wants air preconditioning in the interior of the vehicle, the driver will activate the heating and/or cooling units that are present for this purpose prior to the actual use of the vehicle. As soon as the driver opens the interior of the vehicle, he would like the warm or cold air to stream towards him.
The inventive method for air preconditioning a stopped (shut-off) motor vehicle by way of a heating and/or cooling unit, which draws its energy for heating and/or cooling from an electric storage unit, is characterized in that the heating and/or cooling unit can be operated in at least two output stages. When the heating and/or cooling unit is activated by means of a vehicle external operator control element, the heating and/or cooling unit is activated initially in a first output stage. If the predetermined conditions are fulfilled, the heating and/or cooling unit is switched into a second output stage, where the second output stage generates a higher heating or cooling output than the first output stage.
The inventive method and/or the correspondingly designed motor vehicle offer(s) the advantage that only a small amount of energy is consumed initially, and not until later when a switch is made to the second output stage, is more energy then consumed. In this way, the period of time for air preconditioning (climatizing) can be extended.
This method is especially beneficial for motor vehicles which are equipped with a hybrid engine system. In this case, a system for driving the wheels is designed as an electric motor, which draws its energy from an electric storage unit. This electric storage unit is also used for heating or cooling the interior of a stopped vehicle.
The activation of the air preconditioning process by way of the vehicle external operator control element can occur in a number of different ways. The operator control element can be integrated into a separate remote control unit or in its key unit. In this case, both a joint and separate operator control element for starting a heating process and/or for starting a cooling process can be provided.
The first output stage can be designed in a variety of different ways. In a first alternative, the first output stage is designed such that only a flushing process of the interior of the vehicle is initiated. That is, the air in the interior of the vehicle is blown out of the interior of the vehicle. This output stage offers itself, for example, when the interior of the vehicle is hot, and the driver wants cooling. Since this output stage needs just a very small amount of energy, this embodiment of the output stage is advantageous when the charge state or the capacity of the electric storage unit (accumulator) is very low, since in this case no active cooling of the interior of the vehicle occurs.
In a second alternative, the first output stage can be designed such that in a first step a flushing process of the interior of the vehicle is initiated, and then in a second step the heating and/or cooling unit is operated at low or average capacity. This embodiment of the first output stage is particularly beneficial when the air in the interior of the vehicle is hot and the driver wants a cool vehicle interior, and the charge state of the electric storage unit is sufficient to facilitate an active cooling of the interior of the vehicle at low or average capacity.
In a third alternative, the first output stage can be designed such that without the previous flushing of the interior of the vehicle, the heating and/or cooling unit is run at low or average capacity. Such an embodiment of the first output stage is particularly beneficial when the charge state of the electric storage unit is adequately high, and flushing the interior of the vehicle would not yield any improvement with respect to heating or cooling the interior of a stopped vehicle.
Depending on whether only one or several of the afore-mentioned first output stages can be carried out by the heating or cooling unit, the heating and/or cooling unit (or rather its control unit) automatically selects, on activation of the heating and/or cooling unit in the stopped state, the corresponding first output stage as a function of the selected type of temperature control, the temperature in the interior of the vehicle, and/or the outside temperature and/or the charge state of the electric accumulator.
It is advantageous in the case of a first output stage, which implements exclusively a flushing process of the interior of the vehicle, to design the second output stage in such a manner that the heating and/or cooling unit is run at low or average capacity and/or in such a manner that the heating and/or cooling unit is run at high capacity. If both embodiments of the second output stage can be carried out by the heating or cooling unit, then the heating and/or cooling unit, or rather its control unit, ideally selects the second output stage as a function of the charge state of the electric storage unit. If the charge state is very low, then the output stage, in which the heating and/or cooling unit is run only at average capacity, is selected as the second output stage. Thus, a very high discharging of the electric storage unit and an associated shutting-off of the heating and/or cooling unit, in the event that the charge state falls to a predetermined lowest limit, is prevented.
In a first output stage, in which the heating and/or cooling unit is run at low or average capacity, the second output stage can be designed such that the heating and/or cooling unit is run at high capacity. This embodiment is possible only if the charge state of the electric storage unit is adequate for the air preconditioning at high capacity for a predetermined period of time.
An additional aspect of the invention consists of specifying a suitable change-over time from the first output stage to the second output stage. The change-over time should be selected in such a way that, as soon as the driver gets into the vehicle, he has the feeling that his request for air preconditioning is being considered. To this end, an advantageous embodiment of the invention provides, therefore, that a switch is made from the first output stage to the second output stage, when the luggage compartment or a vehicle door, preferably the driver's vehicle door, is unlocked or opened. Depending on the configuration of the unlocking system of the motor vehicle, the vehicle is unlocked when the driver activates a corresponding operator control element of a remote control unit, when he and/or a remote control unit is (are) detected inside a predefined region around the vehicle, or when he unlocks the vehicle manually with a key at the lock of a door or the luggage compartment. Whether an activation process of the second output stage ensues upon unlocking the vehicle or upon opening a vehicle door, such as the driver's vehicle door, can be permanently predefined or can ensue as a function of the charge state of the electric accumulator. In this context, when the charge state is low, the switch-over process from the first output stage to the second output stage should not take place until as late as possible, preferably not until the driver's door of the motor vehicle is opened.
If the inventive method is implemented in a vehicle of the type, in which the energy to start the motor vehicle is drawn from the same electric storage unit, then it is especially important to monitor the charge state of the electric storage unit. In one advantageous embodiment of the method according to the invention, the heating and/or cooling unit should not be activated or deactivated in the case of a charge state of the electric storage unit that is or falls below a predetermined limit value so that the start-up process remains guaranteed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawing.